The development of plasmid vectors useful for recombinant DNA genetics among microorganisms is well known. The editorial in Science, Vol. 196, April, 1977, gives a good summary of DNA research. This editorial is accompanied by a number of supporting papers in the same issue of Science.
Plasmid pBR322 is a well known plasmid which can be obtained from E. coli RR1, NRRL B-12014. The restriction endonuclease map for pBR322 is published; Sutcliff, J. G. "pBR322 restriction map derived from the DNA sequence: accurate DNA size markers up to 4361 nucleotide pairs long." Nucleic Acids Research 5, 2721-2728, 1978. This map is incorporated herein by reference to the above publication.